Absorption refrigerating system



y 1951 P. EDBERG ETAL 2,983,117

ABSORPTION REFRIGERATING SYSTEM Filed July 30, 1958 2 Sheets-Sheet 1 122 4 75 y & 9

FlG' INVENTORS PER EDBERG EDWARD M. STUBBLEFIELD ATTORNEYS United StatesPatent ABSORPTION REFRIGERATING SYSTEM Per Edberg and Edward M.Stubblelield, La Crosse, Wis., assignors to The Trane Company, LaCrosse, Wis., a corporation of Wisconsin v Filed July 30, 1958, Ser. No.752,070

8 Claims. (Cl. 62-476) This invention relates to absorptionrefrigerating systems and more particularly to an absorptionrefrigerating system including means for circulating fluids in thesystem. Systems of this type generally have portions which operate atless than atmospheric pressure and therefore it is desirable to avoidrunning seals between the interior of the pump and the atmosphere. Suchrunning seals provide some opportunity for air to leak into the system.The presence of air in the system reduces the efliciency, and it must beremoved by a purge'apparatus.

It is an object of this invention to provide hermetic pumps forcirculating the fluids of an absorption system.

It is another object of the invention to lubricate and cool the pumpswith the fluids being circulated or one of the fluids being circulated.1

It is still another object of the invention to provide for the pumpscirculating absorbent solution, a higher pressure in the lubricant thanin the discharge of such pumps so that any leakage past the seal will beleakage of lubricant into the absorbent rather than leakage of absorbentinto the lubricant.

It is another object of the invention to lubricate the absorbentsolution pumps from fluid taken from the discharge side of therefrigerant circulating pump.

Other objects and advantages of this invention will become -apparent asthe specification proceeds to describe the invention with reference tothe accompanying drawings in which:

Fig. 1 is a diagrammatic section of the absorption refrigerating systemincluding the fluid circulating system;

Fig. 2 is a cross section view through the axis of a typical circulatingpump.

Referring now to Fig. 1, the absorption system shown has a single shell10 enclosing a condenser 12, a generator 14, and evaporator 16 and anabsorber 18. It should be understood that other arrangements might beused; for instance, the generator and condenser might be in one shelland the absorber and evaporator might be in a sec- 0nd shell withconduits therebetween for conducting fluids.

The absorber 18 has a coil 20'supplied with cooling fluid'from a source22 to remove heat from the absorber. This cooling fluid is conducted bya conduit 24 to a cooling coil 26 in the condenser 12 and the coolingfluid leava the machine through a conduit 28. The cooling coil 26 in thecondenser 12 removes heat from and condenses the vapor in the condenser.

The generator 14 has a heating coil 30 supplied with heating fluid froma source 32. The heating fluid is discharged from the coil 30 through aconduit 34. The coil 30 heats the absorbent solution in the generatorcausing it to boil and force refrigerant vapor into the condenser 12.The condensed fluid in the condenser 12 flows through an opening 36 intothe evaporator 16. The absorbent solution in the absorber 18 reduces thepressure in the absorber 18 and in the evaporator 16 by the absorptionof water vapor, thus causing the refrigerant in the Patented May 9, 1961evaporator 16 to boil. A low temperature is thus main-' tained in theevaporator 16..

Evaporator 16 has a coil 38. Fluid from a refrigerating load such as anair conditioning system enters the coil 38 through a conduit 40. Thisfluid is reduced in temperature in the coil 38 and returns to therefrigerating load through conduit 42. The liquid refrigerant inthe hasa discharge conduit 56 for conducting the absorbent under pressure to aspray tree 58 in the absorber 18. Absorbent fluid also flows from theabsorbent through a conduit'60 to anl'absorbent fluid pump 62 which hasa discharge conduit 64 for conducting fluid to a heat exchanger 66 andthence to the generator 14 through a conduit 68. Concentrated absorbentsolution flows from the generator 14 through a conduit 70 to heatexchanger 66 and thence through conduit 72 to the absorber 18.

Although various refrigerants and absorbents are used in absorptionrefrigerating machines, for the purpose of explanation it will beassumed that the refrigerant is water and that the absorbent is a saltsuch as lithium bromide or lithium chloride.

The pumps 46, 54 and 62 are generally similar in construction andalthough Fig. 2 shows a typical construction, it will be referred to aspump 46.

Refrigerant from the conduit 48 is conducted to the motor 75 of the pump46 through a conduit 74. This refrigerant serves to cool and lubricatethe motor 75 of the pump 46. A conduit 76 conducts the refrigerant fromthe pump 46.to the conduit 44. Referring now to pumps 62 and 54,refrigerant lubricant and coolant are conducted to the pump 62 fiom theconduit 48 through conduits 78 and 80, and refrigerant lubricant andcoolant are conducted to the pump 54 from the conduit 48 throughconduits 78 and 82. Refrigerant lubricant and coolant flow from the pump62 to the conduit 44 through conduits 84 and 86, and the refrigerantlubricant and coolant flowfrom the pump 54 to the conduit 44 throughconduits 88 and 86. I

Assuming now thatFig. 2 shows pump 46, a pump housing 90 has its inletconnected to conduit. 44 and its discharge connected to conduit 48.Motor 75 is held to pump housing 90 by clamps 92 and bolts 94. A gasket96 is pinched between the pump housing 90 and the end cap 98 of themotor 75 thus providing a vacuum. seal between the pump housing 90 andthe end cap 98 of the motor.

The motor 75 has another at cap 100. A shell 102- extends between-and iswelded to the end caps 98 and I cap 100 and cover plate 104.

A bearing plate 110 is secured to end cap 98 by bolts 112. Bearing plate110 supports a carbon bearing liner 114 which rotatably supports a motorshaft 116. End cap supports the bearing 117 which has a carbon bearingliner 118 which also rotatably supports shaft 116. Although I prefercarbon as a material for the bearing liners, ceramic materials can beused. The bearing liner 118 has grooves (not shown) for the passage oflubricant longitudinally of the bearing. A Kingsbury type of thrustbearing indicated generally by numeral 120 supports the shaft 116 on thebearing plate A seal housing 122 is supported in the bearing plate 110and carries a spring 124 which engages and urges a stationary seal ring126 of carbon or other suitable material against a seal ring 128 ofmetal or other suitable material which rot-ates with by 'a nut 134. Thelubricant and coolant flowing into the motor 75 through the conduit 74flow down through a central passageway 136 in the shaft 116. Thelubrica'nt.

flows through radial passageways 138 to the thrust bearing 120tolubricate the same. Lubricant also flows through passageways 140 to thebearing liner 114 and to the seal rings 126 and 128 to lubricate theseparts.

A cylindrical liner- 142 is expanded at one end into intimate contactwith the end cap 98 and it is welded thereto, and it is expanded at itsother end into intimate contact with the end cap 100 and it is weldedthereto. An O-ring '144 of neoprene or similar material provides a sealbetween liner 142 and end cap 110.

The lubricant fluid discharged from the bearing liner 114 and from thethrust bearing 120 flows upwardly in the cylindrical liner 142 passingthrough the gap 145 between the rotor 146 and the liner 142. Thelubricant then flows through holes 148 in the bearing 116 and thenceinto the conduit 76. It should be understood that the lubricant passingthrough the motor removes heat from the motor.

The stator '150 of the motor '75 is embedded in an epoxy resin 1 52which prevents moisture from reaching the windings 154 of the stator.Electrical conduits for the stator 150 enter the motor 75 through anadapter 156.

The impeller of the pump 46 is designed with sufiicient diameter toproduce a dischargepressure greater than that produced by the pumps 54'and 62 in order that the refrigerant lubricant conductedto the lattertwo pumps will be at a greater pressure than the discharge pressure ofsuch pumps. Therefore, any. leakage through the seals of the pumps 54and 62 will be in a direction from the lubricant side of the seal to thepump housing side of the seal. The entrance of the absorbent solutioninto the motors of pumps 54 and 62 is thus prevented.

Although we prefer to lubricate and cool the pumps 54 and 62 usingrefrigerant, each may be cooled and lubricated with the solution whichit is pumping in the same manner in which the pump 46 is cooled andlubricated with the fluid which it is pumping.

While a specific embodiment of the invention has been described indetail, it is contemplated that various modifioations may be madewithout departing from the scope or spirit of the invention and wedesire to be limited only by the claims.

We claim:

1. In an absorption refrigerating stystem, the combination of anabsorber, an evaporator, a generator and a condenser, means forcirculating refrigerant in said evaporator, a pump for pumping absorbentfrom said absorber to said generator, a motor having a shaft connectedto and driving said pump, means for conducting refrigerant from saidrefrigerant circulating means through said motor to lubricate and coolsaid motor, said refrigerant circulating means being constructed todeliver refrigerant to said motor at a higher pressure than the pressureof absorbent delivered by said pump.

2. In an absorption refrigerating system, the combination of anabsorber, an evaporator, a generator and a condenser, means forcirculating refrigerant in said evaporator, a pump for circulatingabsorbent in said absorber, a motor having a shaft connected to anddriving said pump, means for conducting refrigerant from saidrefrigerant circulating means through said motor to lubricate and coolsaid motor, said refrigerant circulating means being constructed todeliver refrigerant to said motor at a higher pressure than the pressureof absorbent delivered by said pump. a

3. In an absorption refrigerating system, the combination of anabsorber, an evaporator, a generator and a condenser, a first pump forcirculating refrigerant in said evaporator, a second pump for pumpingabsorbent from said absorber to said generator, a motor having a shaftconnected to and driving said second pump and means for conductingrefrigerant fi'orrr the discharge side of said first pump through saidmotor to lubricate and cool said motor.

4. An absorption refrigerating system according to claim 3 having meansfor conducting refrigerant from i said motor to said first pump.

' 5. In an absorption refrigerating system, the combination of anabsorber, an evaporator, a generator, and a condenser, a first pump forcirculating refrigerant in said evaporator, a second pump forcirculating absorbent in said absorber, a motor having a shaft connectedto and driving said second pump, and means for'conducting refrigerantfrom the discharge side of said first pump through said motor tolubricate and cool said motor.

6. An absorption refrigerating system according to claim 5 having meansfor conducting refrigerant from said motor to said first pump.

7. In an absorption refrigerating system, the combination of anabsorber, an evaporator, a generator, and a condenser, a first pump forcirculating refrigerant in said evaporator, a second pump forcirculating absorbent in said absorber, a first, motor having a shaftconnected to and driving said second pump, a third pump for pumpingabsorbent from said absorber to said generator, a second motor having ashaft connected to and driving said third pump, means for conductingrefrigerant from the discharge side of said first pump through saidfirst motor and said second motor to lubricate and cool said first motorand said second motor.

8. An absorption refrigerating system: according to claim 7 having meansfor conducting refrigerant from said first motor and said second motorto the inlet of said first pump.

References Cited in the file of this patent UNITED STATES PATENTS

